The present invention is directed to quick-connect hose end couplings. More particularly, the present invention is directed to quick-connect couplings wherein the couplings couple hoses to fittings in a non-rotational relationship.
Pneumatic devices, such as air brakes, are widely used in the automotive industry. Typically compressed air stored in tanks is applied to air brake operating mechanisms through flexible hoses which have couplings at both ends that couple with male stem members. If the ends tend to twist with respect to one another, collets within the couplings wear quite rapidly which can lead to failure of the collets and thus the coupling.
Current non-rotational couplings have collets in bodies made of brass which tend to wear due to vibration when hoses with which the couplings are used are not pressurized. Moreover, there are plant capacity limitations when brass collets and brass fitting bodies are used. In that brass components are expensive, significant cost reductions are available by not utilizing brass components. In addition, there are advantages to using non-brass components because devices such as hose end bodies which have a 90 degree bend are much easier and less expensive to produce when they are not made of brass.
In addition, there is need to provide a coupling configuration which acts directly on a collet to prevent rotation of the collet when the coupling is engaged as well as arrangements which resist clogging of collets by dirt and foreign objects.
Couplings which are pressurized infrequently but still have significant and continuous vibration applied thereto tend to wear if the collets associated therewith are allowed to rotate or move due to vibration. This phenomenon can reduce the life of coupling components and needs to be addressed.
A continuing concern with respect to an manufactured product is the cost of the components. Accordingly, when a component can be made of molded plastic rather then machined metal it is usually less expensive. Moreover, the component will have fewer critical dimension characteristics which has a tendency to increase reliability and to further decrease costs.
Quick-connect air brake couplings frequently utilize collets machined to close tolerances. Therefore, the collets tend to be relatively expensive. In addition, the female portions of the quick-connect coupling used for air brakes are machined of brass which is of course very expensive. Moreover, in many prior art arrangements, an O-ring seal is installed in the female member increasing chances for damage during assembling.
Metal adapters which are in the form of a male stem member frequently require a wobble broach machining process which is a complex operation, in order to reduce costs it would be desirable to use standard hex-bar stock, rather then bar stock which is not standard.
If possible, it would be desirable to reduce the number of molds to purchase by reducing the number of molded parts. Morever, by reducing the number of molded parts the need to join the parts by spin welding or ultrasonic welding is eliminated. During maintenance and repair, if O-rings are within the female member, replacement is more difficult because damaged O-rings are not visible. Consequently, assembly and replacement is neither simple nor instinctive. With a plastic molded part, it is advantageous to have an anti-rotation hex which is larger because a larger hex facilitates assembly. Generally, there is a need for possible reduction of close tolerances on various components in order to facilitate assembly, reduce costs and increase reliability. Moreover, current quick-connect arrangements do not provide a clear visual indication that the coupling is locked in its connected position because the locking collet is almost completely within the female component. Consequently, there is the danger that the coupling may separate during testing or in the field.
In view of the aforementioned considerations, there is a need for improvements in hose couplings which have a non-rotational connection with male stem members.
In a first general embodiment the present invention is directed to a coupling arrangement or coupling a hose to a male stem having a non-circular end portion and a groove adjacent that end portion. The invention comprises a fitting body having a bore and first end portion adapted for connecting with a hose, and a second end portion adapted to receive the male stem. The body has a non-circular section adapted to receive a non-circular end portion of the stem as well as a sealing section between the non-circular section and the first end portion. A cap member is disposed in fixed relation at the first end of the fitting body, the cap member having axially extending lugs with axially extending spaces therebetween which extend into the bore of the body. A collet is seated within the cap member, the collet having axially extending arms received within the axially extending spaces between the axially extending lugs of the cap wherein the collet is restrained from rotation within the cap. The arms of the cap have a first detent thereon adapted to be received in the groove on the male stem to lock the stem within the fitting body when the collet is in a locked position. A seal is disposed in the sealing section of the fitting body between the lugs and is adapted to engage the male stem in a radial direction.
In accordance with a further aspect of the invention, the collet, body and cap are made of a plastic material.
In further aspects of the invention, the lugs on the cap have inwardly extending ribs for engaging the male stem adjacent the groove in the stem and the arms of the collet have externally projecting ribs which are received on lands in spaces between the axially extending lugs of the cap when the collet is in the locked position. In still further aspects of the invention, the arms and lugs have end faces which face the seal wherein the end faces of the lugs on the cap engage the seal to keep the seal from extruding between the arms of the collet.
In accordance with a second embodiment of the invention, the invention is directed to a coupling arrangement or coupling a hose to a male stem member having a non-circular portion thereon and a locking groove therein exposed between an insertion end and a coupling end. The invention comprises a female member having a first end portion adapted for connecting with the hose and a second end portion configured as a socket for receiving the male stem member. The female member includes a non-circular section adapted to receive the non-circular portion of the male stem member; a sealing section between the non-circular section and the first end portion, and a locking section. The locking section includes a first axially facing, radially extending shoulder and a radially opening slot. A substantially annular detent is inserted through the radially opening slot in the female member and disposed within the locking section of the female member. The substantially annular detent is received in the locking groove in the male stem member and has a first axially facing surface for engaging the axially facing, radially extending shoulder of the female member when the non-circular portion of the male stem member is within the non-circular section of the female member. Thus, the male stem member is rotatably and axially locked within the female member.
In a more specific aspect of the second embodiment of the invention, the detent member has a selected width in the axially direction and is mounted within an arcuate cavity having an axial extent greater then the selected width of the detent. Upon pressurizing the coupling arrangement with internal fluid pressure, the male stem member moves in a direction away from the female member engaging the axial facing surface of the detent member with the first axially facing, radially extending shoulder of the female member.
In another aspect of the invention, the arcuate cavity has a first section which is radially unobstructed allowing radial movement of the substantially annular detent and a second section having blocking elements which inhabit radial movement above the annular detent.
In other aspects of the invention, the substantially annular detent is substantially C-shaped allowing detent to be radially slipped through the radially opened slot in the female member and allowing the substantially annular detent to expand radially to receive the male stem member therethrough and to thereafter contract into the groove in the male stem member.
In accordance with additional aspects of the invention, the female member and substantially annular detent are both made of plastic material.
In still another aspect of the invention, the male stem member is made of metal hex-bar stock.
Upon further study of the specification and appended claims, further features and advantages of this invention will become apparent to those skilled in the art.